1. Technical Field
The present disclosure relates to a light source device.
2. Description of Related Art
A transmissive liquid crystal display device generates perceivable images using light emission from a backlight light source provided in a back surface of a liquid crystal panel. There has been proposed a backlight device (backlight light source) having a blue light emitting element, a green phosphor, a red phosphor, and a filter material that attenuates the light in the wavelength region of 570 nm to 590 nm. As such a filter material, neodymium oxide and neodymium glass have been proposed (see, for example, Japanese Unexamined Patent Application Publication No. 2012-199288).
In a white light source using a blue light emitting element, a green phosphor, and a red phosphor, there is only a small overlap of emission spectra of the blue light emitting element and the green phosphor, but there is a large overlap of emission spectra of the green phosphor and the red phosphor at a particular wavelength region, which substantially corresponds to yellow light. As a result, a light source using both a green phosphor and a red phosphor tends to have an emission spectrum having a high intensity in the yellow wavelength region.
With regard to color filters provided on a liquid crystal panel, there is also an overlap of transmission spectra of a green filter and a red filter at the above described particular wavelength region. As a result, when a green color is represented by the liquid crystal panel, the light transmitted through a green filter includes pure green light and yellow light. Similarly, the light transmitted through a red filter includes pure red light and yellow light.
The backlight light source disclosed in Japanese Unexamined Patent Application Publication No. 2012-199288 includes filter material that attenuates the light in the wavelength region of 570 nm to 590 nm, which corresponds to the above described particular wavelength region, so that the backlight light source has an emission spectrum having a low intensity in the yellow wavelength region.